Generalized Likelihood Signal Resolution

This Paper Defines an M-Ary Generalized Likelihood Ratio Test (MGLRT) that overcomes Root\u27s Early Objection to the Application of Generalized Likelihood Ratio Testing to the Resolution of Correlated Signals. the Proposed Test Extends the Form of a Conventional Binary Generalized Likelihood Ratio Test (GLRT) in a Manner that Permits a Generalization of the Minimax Properties of the Binary Test to the M-Hypotheses Case. When the Estimated Signals Are Orthogonal, the Test Reduces to a Sequence of Conventional Binary Tests Duplicating the Performance of a Narrow-Band Matched Filter Envelope-Detector Receiver. © 1975, IEEE. All Rights Reserved

A range expanding signal conditioner

Telemetry system modifications to improve signal resolution are described. Process uses zero suppression technique which consists of subtracting known voltage from input and amplifying remainder. Schematic diagram of circuit is provided and details of operation are presented

A microprocessor based anti-aliasing filter for a PCM system

Described is the design and evaluation of a microprocessor based digital filter. The filter was made to investigate the feasibility of a digital replacement for the analog pre-sampling filters used in telemetry systems at the NASA Ames-Dryden Flight Research Facility (DFRF). The digital filter will utilize an Intel 2920 Analog Signal Processor (ASP) chip. Testing includes measurements of: (1) the filter frequency response and, (2) the filter signal resolution. The evaluation of the digital filter was made on the basis of circuit size, projected environmental stability and filter resolution. The 2920 based digital filter was found to meet or exceed the pre-sampling filter specifications for limited signal resolution applications

Signal analysis of impulse response functions in MR- and CT-measurements of cerebral blood flow

The impulse response function (IRF) of a localized bolus in cerebral blood flow codes important information on the tissue type. It is indirectly accessible both from MR- and CT-imaging methods, at least in principle. In practice, however, noise and limited signal resolution render standard deconvolution techniques almost useless. Parametric signal descriptions look more promising, and it is the aim of this contribution to develop some improvements along this line.Comment: 15 pages, 6 figure

Static-light mesons on a dynamical anisotropic lattice

We present results for the spectrum of static-light mesons from Nf=2 lattice QCD. These results were obtained using all-to-all light quark propagators on an anisotropic lattice, yielding an improved signal resolution when compared to more conventional lattice techniques. In particular, we consider the inversion of orbitally-excited multiplets with respect to the `standard ordering', which has been predicted by some quark models.Comment: 3 pages with 3 figures. Talk by JF at "Quarks and Nuclear Physics", Madrid 5th-10th June 200

Radial and orbital excitations of static-light mesons

We present results for the spectrum of static-light mesons from Nf=2 lattice QCD. These results were obtained using all-to-all light quark propagators on an anisotropic lattice, yielding an improved signal resolution when compared to more conventional lattice techniques. With a light quark mass close to the strange quark, we have measured the splittings between the ground-state S-wave static-light meson and higher excitations. We attempt to identify the quantum numbers of the excited states in the context of the reduced spatial symmetries of the lattice.Comment: 14 pages, 10 figure

Nanometer-scale Tomographic Reconstruction of 3D Electrostatic Potentials in GaAs/AlGaAs Core-Shell Nanowires

We report on the development of Electron Holographic Tomography towards a versatile potential measurement technique, overcoming several limitations, such as a limited tilt range, previously hampering a reproducible and accurate electrostatic potential reconstruction in three dimensions. Most notably, tomographic reconstruction is performed on optimally sampled polar grids taking into account symmetry and other spatial constraints of the nanostructure. Furthermore, holographic tilt series acquisition and alignment have been automated and adapted to three dimensions. We demonstrate 6 nm spatial and 0.2 V signal resolution by reconstructing various, previously hidden, potential details of a GaAs/AlGaAs core-shell nanowire. The improved tomographic reconstruction opens pathways towards the detection of minute potentials in nanostructures and an increase in speed and accuracy in related techniques such as X-ray tomography

Using Information Theoretic Techniques for Sinusoidal Signal Resolution

The objective is to develop information theoT"€tic criteria for detection of sinusoidal signals. The minimum description length (MDL) and the predictive stochastic complexity (PSC) have been formulated for harmonic resolution. MDL and PSC QI" € the codelength for data and model. The proposed techniques are based on decomposing the observation vector into its components in the signal and noise subspaces. Each component is encoded separately and the results are added to form the total codelength. The codelength is minimized over different models to select the best model. Sinusoidal signal detection is applied in various fields ranging from telecommunications to arra

Electrical noise reduction techniques contributing to improved data quality at the National Transonic Facility

In initial use, the high-speed digital data acquisition systems at Langley Research Center's National Transonic Facility produced data containing unacceptably high noise levels. Described is a process whereby the contributing noise sources were identified and eliminated. The effects of 60 Hz power, system grounding, EMI/RFI, and other problems are discussed and the corrective action taken is outlined. The overall effort resulted in an improvement of greater than 5:1 in system performance. Although the report describes a system specifically used for wind tunnel data acquisition, the corrective techniques employed are generally applicable to large scale high-speed data systems where signal resolution in the low microvolts range is important